Add licensing and copyright information for all files in this repository. This
either happens in the file itself as a comment header or in the file
`.reuse/dep5`.
This commit also adds a Github workflow to check pull requests and adapts
copyright.pl to the changes.
Closes#8869
- Detect all spellings of <file>, <file name> etc as well as <path>.
- Only complete directories for <dir>.
- Complete URLs for <URL>.
- Complete --request and --ftp-method.
Closes#8363
Reported by the new script 'scripts/copyright.pl'. The script has a
regex whitelist for the files that don't need copyright headers.
Removed three (mostly usesless) README files from docs/
Closes#5141